eap-mschapv2: Memzero copies of secrets

This commit is contained in:
Andrew Zaborowski 2019-03-21 03:54:14 +01:00 committed by Denis Kenzior
parent 881fbd1d80
commit 94043d6bcb
1 changed files with 24 additions and 12 deletions

View File

@ -305,7 +305,7 @@ static void eap_mschapv2_handle_success(struct eap_state *eap,
state->user, nt_response);
if (!ret)
goto err;
goto done;
ret = mschapv2_generate_authenticator_response(password_hash_hash,
nt_response,
@ -315,19 +315,19 @@ static void eap_mschapv2_handle_success(struct eap_state *eap,
authenticator_resp);
if (!ret)
goto err;
goto done;
/*
* For iwd timing attacks are unlikly because media access will
* For iwd timing attacks are unlikely because media access will
* influence timing. If this code is ever taken out of iwd, memcmp
* should be replaced by a constant time memcmp
*/
if (len < 42 || memcmp(authenticator_resp, pkt, 42)) {
l_warn("Authenticator response didn't match");
goto err;
ret = false;
goto done;
}
ret = mschapv2_get_master_key(password_hash_hash, nt_response,
master_key);
ret &= mschapv2_get_asymmetric_start_key(master_key, session_key,
@ -336,7 +336,7 @@ static void eap_mschapv2_handle_success(struct eap_state *eap,
16, false, false);
if (!ret)
goto err;
goto done;
eap_method_success(eap);
@ -346,10 +346,13 @@ static void eap_mschapv2_handle_success(struct eap_state *eap,
/* The eapol set_key_material only needs msk, and that's all we got */
eap_set_key_material(eap, session_key, 32, NULL, 0, NULL, 0);
return;
done:
if (!ret)
eap_method_error(eap);
err:
eap_method_error(eap);
explicit_bzero(master_key, sizeof(master_key));
explicit_bzero(session_key, sizeof(session_key));
explicit_bzero(password_hash_hash, sizeof(password_hash_hash));
}
static void eap_mschapv2_handle_failure(struct eap_state *eap,
@ -426,6 +429,7 @@ static int eap_mschapv2_check_settings(struct l_settings *settings,
const struct eap_secret_info *secret;
char setting[64], setting2[64];
uint8_t hash[16];
int r = 0;
snprintf(setting, sizeof(setting), "%sIdentity", prefix);
identity = l_settings_get_string(settings, "Security", setting);
@ -457,7 +461,8 @@ static int eap_mschapv2_check_settings(struct l_settings *settings,
if (password && password_hash) {
l_error("Exactly one of (%s, %s) must be present",
setting, setting2);
return -EEXIST;
r = -EEXIST;
goto cleanup;
}
if (password_hash) {
@ -465,6 +470,9 @@ static int eap_mschapv2_check_settings(struct l_settings *settings,
size_t len;
tmp = l_util_from_hexstring(password_hash, &len);
if (tmp)
explicit_bzero(tmp, len);
l_free(tmp);
if (!tmp || len != 16) {
@ -489,9 +497,11 @@ static int eap_mschapv2_check_settings(struct l_settings *settings,
validate:
if (!mschap_nt_password_hash(password, hash))
return -EINVAL;
r = -EINVAL;
return 0;
cleanup:
explicit_bzero(password, strlen(password));
return r;
}
static bool eap_mschapv2_load_settings(struct eap_state *eap,
@ -517,6 +527,7 @@ static bool eap_mschapv2_load_settings(struct eap_state *eap,
if (password) {
set_password_from_string(state, password);
explicit_bzero(password, strlen(password));
} else {
unsigned char *tmp;
size_t len;
@ -529,6 +540,7 @@ static bool eap_mschapv2_load_settings(struct eap_state *eap,
tmp = l_util_from_hexstring(hash_str, &len);
memcpy(state->password_hash, tmp, 16);
explicit_bzero(tmp, len);
l_free(tmp);
}